The Applicant is aware of various tape transport mechanisms having an operating plate, or the like, carrying recording and/or playback heads into an operative position in which the heads engage a recording tape and an inoperative position in which the heads are out of engagement with the tape. Examples of these mechanisms are shown in U.S. Pat. Nos. 4,393,426 to Nakanishi, 4,399,475 to Shimomae, 4,404,606 to Watanabe, 4,523,241 to Ito et al and D. E. "Offenlengungsschrift" 28 02. 232 to LENCO AG. All the arrangements shown in these patents make use of cam and follower mechanisms to move the operating plate, or the like relative to a base member. Some of these arrangements also make use of solenoids to lock the operating plate, or the like, in its operative position. Various problems are associated with these arrangements. For example, cam mechanisms cannot be subjected to very high forces and hence, in certain applications they cannot be used. Also, with the solenoids their power consumption is high. Heat dissipation can also be a problem with such mechanisms and, hence, their range of applications is limited.